1. Field of the Invention
The invention concerns poly (alkylene oxide) polymers and their processing into shaped forms. More particularly the invention concerns poly (ethylene oxide) homopolymer monofilaments, their preparation and use in weaving and sewing fabrics.
2. Brief Description of the Prior Art
Poly (ethylene oxide) homopolymers are well known as is their preparation and use for a variety of purposes; see for example U.S. Pat. Nos. 2,897,178; 2,982,742; 3,030,231; 3,154,514; 3,167,519; 3,316,676; 3,328,916; 3,377,261; 3,465,070; 3,470,078; and 3,766,101. Although a wide variety of uses are disclosed in the prior art for poly (ethylene oxide) homopolymers they have not, prior hereto, been suggested as suitable monofilaments for any purpose whatsoever.
The production of monofilaments from many different classes of synthetic polymeric resins has been disclosed in numerous publications. For example, U.S. Pat. No. 3,084,991 teaches the production of poly (arylepoxy) ether monofilaments. Ethylene sulfide polymer monofilaments are described in U.S. Pat. No. 3,539,676. In U.S. Pat. No. 3,608,044 disclosure is made of monofilaments prepared from polyoxymethylene homopolymers and copolymers of polyoxymethylene-oxyethylene. In general however, none of the prior art procedures described are known to be suitable for producing satisfactory weaving yarns or threads from poly (ethylene oxide) homopolymers.
Poly (ethylene oxide) homopolymers are characterized in part by unique thermal behavior, crystal structure and extreme crystal instability in the presence of moisture. Prior hereto, their uses have been restricted by these properties to "humectants, thickeners or softeners" (U.S. Pat. No. 3,316,676) and like uses. The latter patent also describes such homopolymers as "normally unsuitable for films or molded objects". However, a number of techniques have been developed for extruding films of poly (ethylene oxide) homopolymers; see for example U.S. Pat. No. 3,328,916. However, the extruded films have not been suggested as useful for purposes requiring tensile strength, etc. Furthermore, the techniques of extruding the films have generally required modifying the homopolymer with additives such as plasticizers and the like because of brittleness. Generally such plasticizer additives degrade the desired properties of a monofilament, i.e.; tensile strength, elasticity etc.; see for example, U.S. Pat. No. 3,154,415 which comments at length on the poor "stress endurance", i.e.; crazing and tensile failure of poly (ethylene oxide) homopolymer film extrudates. In the latter patent, the problem is solved by copolymerizing the homopolymer with a substantial proportion of a wide variety of glycols to alter the polymeric backbone significantly. Such copolymerization of course alters the chemical nature of the extrudates in a major way and requires additional procedural steps.
By the process of the invention, one may prepare monofilaments of poly (ethylene oxide) homopolymers having properties which make the monofilaments useful as weaving yarns and sewing threads, removable from a finished fabric by dissolution in water.
Prior to the invention, the use of soluble yarns and threads as temporary binder yarns or basting threads had been known. Representative of the prior art are U.S. Pat. Nos. 2,714,758 and 3,137,864 which teach removing polyethylene basting yarns in hot wash water or by melting insitu. The disclosure of U.S. Pat. No. 2,539,244 includes the removal of cotton basting threads previously treated with dilute sulfuric acid by heating to disintegrate the thread. More recently U.S. Pat. No. 3,311,928 has described ethyl cellulose, polystyrene, polycarbonate and polystyrenemethylmethacrylate monofilaments or yarns which may be used as basting threads removable in dry cleaning solvents or aqueous acid or alkali mediums. Polyvinyl alcohol weft threads have been used in tire cord fabrics (U.S. Pat. No. 2,898,665) and subsequently removed by dissolution in water. According to the latter patent, dissolution times are generally prolonged unless the water is heated or the monofilament treated with glycerine. The latter expedient weakens the tensile strength of the yarn and is therefore undesired if the yarn is to be used in, for example, a weaving operation.
The use of the poly (ethylene oxide) monofilaments of the present invention in basting procedures or as temporary yarns in weaving fabrics is an improvement in the art because the monofilaments of the invention are removable very rapidly and completely even in cold untreated water. It is not necessary to add acid, alkali or other chemicals to the solvent water nor is it necessary to treat the yarns to weaken them. This is an economic advantage, saving of our natural resources, i.e.; energy, time and labor. The method leaves the finished fabric free of undesirable residues. The method of use is particularly useful in preparing temperature sensitive fabrics etc.